Transaction Details

Footnotes

Represents number of securities owned by EN Holdings LLC, which is owned by the reporting person and his affiliates. | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.76 to $67.75. The Reporting Person undertakes to provide Interactive Brokers Group, Inc. (the "Company"), any security holder of the Company, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each price within the ranges set forth in footnotes (2) - (7) to this Form 4. | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $67.76 to $68.04. | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $63.18 to $64.17. | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $64.18 to $65.17. | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $65.18 to $66.17. | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $66.18 to $67.06. | This amount includes (a) Class A common stock attributable to vested restricted stock units that were awarded under the amended 2007 Stock Incentive Plan ("Plan") and (b) unvested restricted stock units that were awarded under the Plan.